Clinical Neutron Therapy System

The Clinical Neutron Therapy System (CNTS) at the University of Washington Medical Center (UWMC) is a cyclotron-based radiation therapy machine. It has been treating patients and making isotopes since 1984, and is maintained and upgraded by UWMC staff.

In 1999 we replaced the therapy portion of the vendor's original control system with new hardware and our own software.

In 2015 we replaced the therapy control system again, this time using EPICS, the Experimental Physics and Industrial Control System.

This paper from the ICALEPCS 2013 conference describes the design of the 2015 system:

This presentation (including abstract and slides) at the Fall 2016 EPICS meeting discusses the 2015 system and its formal verification, including several automated tools:


This section documents the 1999 control system and its development project. The functionality and user interface (but not the internals) of the 2015 system are similar, so most of these are still pertinent.

This report provides an overview and summary of that project:

These reports describe that control system in detail. Its Reference manual now serves as the primary requirements document for the 2015 system, and much of the Therapist's guide remains accurate.

The old Operations manual and Implementation guide depend on internals so they are now obsolete, but are retained here to demonstrate what kind of information is needed to support a maintainable system.

This brief conference paper describes how we used formal software development methods (the Z notation and the SMV model checker) in that project:

Here is a large portion of the formal specification itself. Since it describes functionality but not internals, most of it applies to the 2015 system as well.

Here are some brief notes for a talk about the project.


This section provides documents from the years preceding the 1999 installation.

These served as our specifications during development of that system. They have been largely superceded by the Reference Manual (above), which is organized differently and incorporates changes made during development and after the initial installation.

These early papers and reports record preliminary work leading to the 1999 installation.

Some examples suggested by this project appear in a textbook.


Jonathan Jacky / Department of Radiation Oncology Box 356043
University of Washington / Seattle, Washington 98195-6043 / USA
Tel (206) 598-4117 / Fax (206) 598-6218

E-mail: jon@u.washington.edu